Ichigo and the stranger faced off in the heart of the forest, the air thick with tension. Ichigo's Zanpakuto, Zangestsu, hummed with energy over his shoulder, mirroring the spearman's ready stance across from him.

'So, tell me...' Ichigo's voice cut through the silence, his eyes narrowing. 'Are you some kind of Fullbringer, or maybe you've got a grudge against the Shinigami?' The stranger merely smirked, his expression unreadable.

'Sorry, kid,' he drawled, his tone even but with an undercurrent of danger, 'but my orders are to silence spies and witnesses. And you, unfortunately, fall into the latter category.' With that, he dropped into a fluid fighting stance, his spear at the ready.

Ichigo's gaze hardened; the time for questions had passed. With a practiced motion, he readied Zangestsu, its familiar weight comfort in his hands. In the blink of an eye, the two clash, their movements a deadly dance of steel. The spearman spun and leaped, his spear slicing the air with deadly precision, each strike aimed to kill. Ichigo met him head-on, his movements fueled by instinct and years of battle-honed experience. He blocked, parried, and dodged, his senses stretched to their limits.

The spearman's eyes flickered with surprise; his opponent was holding his own. With a swift decision, he increased his speed, his spear flashing in the dappled forest light, its strikes nearing the speed of light itself. Ichigo found himself on the back foot, his focus solely on survival. Then, in a heartbeat of opportunity, the spearman struck, his spear thrusting forward with the intent to impale.

But Ichigo was no ordinary fighter. At the last possible moment, he used Shunpo, his body vanishing and reappearing behind the stunned spearman. The sudden reversal left the man scrambling to defend himself, his spear barely meeting Ichigo's swift counterattack, with the force of their clash sent the spearman skidding across the forest floor, his eyes wide with shock.

'The Hell!?' he stuttered, his mind reeling. 'How did he manage to move so fast? Even the Shinigami I've killed couldn't manage that when they used that technique!' Ichigo's expression turned grim, his focus locked on his foe.

'This guy is definitely, strong...' He analyzed, subtly shifting his stance. 'But it's his speed that makes him dangerous. And that spear...' his gaze flicked to the weapon, '...it's bound to have an ability he hasn't shown yet.' A spark of determination ignited in his eyes. 'Which means I need to end this before he has a chance to use it!.' Ichigo then began to draw upon his spiritual power, his body erupting into a blazing aura of yellow energy that made the spearman's eyes go wide.

'What the...?!' the man's thoughts screamed in panic. 'What is that kid's Zanpakuto doing?!' he nearly screamed before proceeding to rush towards Ichigo. 'I have to take him down, be' but his words were cut off as Ichigo vanished and reappeared right in from before him. Zangestsu, now surged with power, its blade shining brighter than the sun itself.

'Getsuga Tensho!' Ichigo bellowed, his blade flashing forward. From its edge erupted a colossal blast of spiritual energy that formed as a wave of unstoppable power that threatened to consume everything in its path. Yet the spearman by using all of his reflexes nearly pushed past his limits managed to barely avoid the attack, by dodging beneath the wave. When he rose back up he saw to his shock that dozens upon dozens of trees behind him had their upper parts completely vaporized and when he looked up into the sky he saw that one of the large clouds had been split completely in two.

'That…bastard…' the spearman breathed in dread, his gaze locked on Ichigo with a mix of fear and respect. 'Not only does this human have Shinigami powers on par with a Servant and speed to match my own...' his eyes narrowed, '...but he wields a Zanpakuto on the level of an anti-fortress Noble Phantasm. And unlike most, he can use it again and again without seeming to tire.' His grip on his spear tightened. 'If I'm to defeat this Shinigami, I have no choice but to unleash this…'

'I'll admit, kid,' the spearman said, his voice dropping to a menacing growl, 'you're far stronger than I gave you credit for.' His features twisted into a feral snarl. 'But now, it's time I take your heart!' His spear ignited, its length ablaze with a burning, blood-red energy. The air around it rippled with heat as he prepared to strike, while Ichigo raised Zangestsu in desperate defense.

The spearman drew back his arm, his lips curling into a snarl. 'Gae Bo-!?' he began, but his words were cut off as a black-clad connected squarely with his cheek, sending him flying into the underbrush with bone-jarring force. As he struggled to regain his feet, his gaze fell upon a figure emerging from the trees. Yasutora 'Chad' Sado stood tall, his dark eyes fixed on the spearman, his expression unreadable and fullbring Brazo Derecha de Gigante activated. His left arm was clad in a black solid liquid while with a pointed shoulder extension and highlighted with light tribal magenta markings.

'Chad!?' Ichigo called, a note of surprise in his voice. Sado lowered his clenched fist, a small smile playing on his lips. 'Felt trouble brewing in Karakura. Figured you could use a hand taking down this guy.' Ichigo's lips curled into a smirk. 'I had him handled, but...thanks for the assist, anyway.' The spearman glared at them, his face twisted with pain and anger. He rubbed at his cheek, feeling like one of his teeth was loose. His gaze turned towards Sado, standing ready to defend his friend, and a spark of frustration ignited in the man's eyes.

'Screw this...' he muttered before spitting out blood from his mouth. 'I came to this city to silence a witness, but I should have known better than to think a Shinigami would fight alone. I'm not about to risk my neck on a losing battle just yet.' Ichigo's grip on Zangestsu tightened, a growl rising in his throat. 'So you're running, then?' he taunted, but the spearman merely snorted.

'If you want a rematch, kid, you know where to find me – Fuyuki city.' With that, he spun on his heel, his form beginning to shimmer as he entered his spirit state. But before he vanished, his red eyes locked onto Ichigo, burning with a promise of bloodlust. 'But next time, your friends won't be there to save you when I will take your heart…'

The mysterious warrior then disappeared while Ichigo looked on determined to be ready to face the spearman again in their next battle.

Later that day, Ichigo and his companions escorted the wounded Shinigami officer to Urahara's shop. The shopkeeper quickly contacted the Gotei 13, who dispatched the 4th Division to retrieve the officer and transport him back to the Soul Society. As they waited, Renji and Rukia arrived, their faces etched with concern and Ichigo immediately explained the situation to them.

'Yeah, the guy was insanely strong,' Ichigo explained, 'Had this red spear he used to wipe out the Shinigami patrol investigating the Holy Grail War in Fuyuki city.' His words sparked a knowing glance among the gathered Shinigami. Uryu hummed thoughtfully, and Ichigo's gaze narrowed. 'You guys know something, don't you?' Renji crossed his arms, looking uncomfortable.

'It's...complicated, Ichigo. As that information is for high-ranking officers only, but...' he trailed off, and Rukia picked up the thread.

'Since you already encountered a servant, you have the right to know regardless...' She then cleared her throat and began her tale. 'The Holy Grail War is a battle royal where seven masters which are human magi, each summoning a Heroic Spirit, legendary warriors from history and myth, to fight on their behalf. With the last remaining Master and Servant standing to claim the Holy Grail. Which is said to be an omnipotent device that can grant any wish'

Ichigo's brow furrowed. 'Wait, you mean wizards and heroes from fairy tales?' He asked, incredulous. 'But wouldn't those guys be in The Soul Society, or Hollows, or...?'

Urahara's hands clasped together, his expression solemn.

'Our world is far more complex than just the cycle of souls, Ichigo. Heroic Spirits are souls that have transcended reincarnation through legendary deeds, mythical figures given life by human belief, or even human souls who've made pacts with the Counter Force Alaya in exchange for power. They exist beyond space and time, in the Throne of Heroes.' He paused, studying Ichigo. 'When summoned, they become Servants. So the man you fought...'

Uryu held his chine in understanding. 'Then he must have been a person from myth or legend...' he then shifted his gaze to Ichigo. 'Kurosake did that look any familiar to any tale you have read?'

Ichigo thought back, his eyes widening. 'Well, I don't read much about that stuff but from what I can recall he had a long red spear with thorns etched into its shaft. He was about to say its name when Chad interrupted...I think it was Gae-Bo...' The name clicked into place, and his eyes went wide. 'Gae-Bolg...the spear from that old Celtic myth!'

Urahara nodded gravely. 'Then the one you faced was Cú Chulainn, the legendary defender of Ulster, said to wield the cursed spear Gae-Bolg that guarantees its victim's death when thrown...or simply activated...'

Ichigo's face paled, a cold sweat breaking out across his brow as he met Sado's gaze. 'Guess you did save my skin back there, Chad' he spouted nervously while rubbing the back of his head.

Sado flashed him a rare smile and then looked back at Urahara. 'So the Soul Society has a problem with these Magi and their Servants?'

Urahara then waved his fan. 'Not exactly...Heroic Spirits exist outside their jurisdiction, due to them not being part of the cycle of reincarnation. And summoning them is nearly impossible for most Magi, due to the vast mana required...' He trailed off, his expression thoughtful. '...but there are exceptions, like the Holy Grail War, which selects seven Magi to be Masters and provides the mana they need to summon them.

Ichigo's frown deepened. 'And the Soul Society is okay with these Masters sending their Servants to slaughter each other?'

Renji's arms remained crossed, his gaze serious. 'The Soul Society doesn't interfere in human affairs, Ichigo. That includes everything from street brawls to global conflicts...and apparently, the Holy Grail War as well. They only involve themselves because a number of the heroes were once human souls,' Renji explained, 'and even then it was agreed that so long as the Masters and Servants don't harm living souls, the Grail Wars can continue'

Rukia's gaze turned downward, her voice taking on a somber note. 'But things changed when the great Fuyuki Fire fire happened...'

Ichigo's mind flashed back to the news reports he'd seen as an eight-year-old, the tragedy taught in his history classes over the years. A chill of dread swept through him. 'The Holy Grail War...caused that?'

Renji's nod was grim, his eyes closing as if in pain. 'The last one did. Ever since the treaty was broken, the Gotei 13 have been monitoring Fuyuki city, to prevent another war...until now.'

Ichigo's fist clenched at his side. 'So what's the Soul Society's play now?'

Rukia's sigh was heavy. 'Honestly, I don't know...but I have no doubt they'll intervene in the war much more directly now...'